DESIGN AND OPTIMIZATION OF A MICROPUMP-BASED ELECTROSPRAY DEVICE FOR PREPARATION OF NITROCELLULOSE SUBSTRATES FOR PLASMA DESORPTION TIME-OF-FLIGHT MASS-SPECTROMETRY

Details of a nitrocellulose (NC) substrate preparation technique in Cf-252 plasma desorption time-of-flight mass spectrometry were investigated using an electrospray device, in which a micropump was employed for solution delivery. The molecular ion yields for three standard proteins (porcine insulin, chicken-egg lysozyme and chymotrypsinogen A) were studied as a function of the electrosprayed NC layer thickness, spray rate, NC solution concentration and some other parameters. Optimal parameters of the NC substrate preparation procedure were determined, which include deposition of a layer of 250-750-mu-g cm-2 at up to 15-mu-l min-1 spray rate and up to 15-mu-g-mu-l-1 solution concentration.